Latch Assembly For Use With An Inversion Drum

ABSTRACT

A hinged cover overlays an opening that provides access to a pressurized inversion drum. A releasable latch assembly holds the cover in a closed and locked position. The latch assembly comprises a plurality of first knuckles formed in the cover that are interlaceable with a plurality of second knuckles formed in the body adjacent the opening. The latch assembly further comprises a rotatable latch pin that may be installed within the first and second knuckles. The latch assembly is moved from an unlocked to a locked position by rotation of the latch pin within the knuckles.

SUMMARY

The present invention is directed to an apparatus comprising a bodyhaving an opening formed therein, a cover sized to cover the opening,and a latch assembly. The latch assembly comprises a plurality of spacedand aligned first knuckles formed in a selected one of the cover andbody, each first knuckle having an exposed semi-cylindrical grooveformed therein, and a plurality of spaced and aligned second knucklesformed in the unselected one of the cover and body adjacent the opening.The latch assembly further comprises a rotatable latch pin havingaligned and alternating first and second sections. Each first section ofthe latch pin has a size and shape complementary to the semi-cylindricalgroove of a first knuckle.

The present invention is also directed to an apparatus comprising a bodyhaving an opening formed therein, a cover sized to cover the opening,and a latch assembly. The latch assembly comprises a plurality ofknuckles formed in a selected one of the cover and body and a pluralityof knuckles formed in the unselected one of the cover and body adjacentthe opening. The plurality of first knuckles are configured to interlacewith the plurality of second knuckles. The latch assembly furthercomprises a rotatable latch pin having a plurality of half-mooncross-sections.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an inversion drum utilizing a latchassembly of the present invention. The latch assembly is shown in anunlocked position.

FIG. 2 is a perspective view of a body and cover configured for use withthe latch assembly. The cover is shown in an open position and the latchassembly is shown in an unlocked position. A latch pin used with thelatch assembly has been removed for clarity.

FIG. 3 is a top plan view of the body and cover shown in FIG. 2.

FIG. 4 is a cross-sectional view of a portion of the latch assemblyformed in the body, taken along line A-A from FIG. 3.

FIG. 5 is a perspective view of the latch pin used with the latchassembly.

FIG. 6 is a perspective view of the body and cover shown in FIG. 3. Thecover is shown in the open position and the latch assembly is shown inan unlocked position. The latch pin is shown installed within the body.

FIG. 7 is a top plan view of the body and cover shown in FIG. 6.

FIG. 8 is a cross-sectional view of a portion of the latch assemblyformed in the body, taken along line B-B from FIG. 7.

FIG. 9 is a top plan view of the cover in a closed position. The latchassembly is shown in an engaged position.

FIG. 10 is a cross-sectional view of the latch assembly in the engagedposition, taken along line C-C from FIG. 9.

FIG. 11 is an enlarged view of area D shown in FIG. 10.

FIG. 12 is a top plan view of the cover in the closed position. Thelatch assembly is shown in a locked position.

FIG. 13 is a cross-sectional view of the latch assembly in the lockedposition, taken along line E-E from FIG. 12.

FIG. 14 is an enlarged view of area F shown in FIG. 13.

FIG. 15 is a perspective view of an inversion drum utilizing analternative embodiment of the latch assembly. The latch assembly isshown in a locked position.

FIG. 16 is an enlarged view of area G shown in FIG. 15.

FIG. 17 is a perspective view of the inversion drum shown in FIG. 15. Aportion of the drum has been cut-away for better display. The latchassembly is shown in an unlocked position.

FIG. 18 is an enlarged view of area H shown in FIG. 17.

FIG. 19 is an enlarged view of area I shown in FIG. 18.

DETAILED DESCRIPTION

Cured in Place Piping (CIPP) operations are performed to repair existingunderground pipes. The operation involves the installation of a resinsaturated, tubular liner within the existing pipe. The resin soakedliner cures against the interior of the pipe and seals any cracks ordamaged areas.

A pressurized inversion drum is used to install the liner within theexisting pipe. The interior of the liner is typically made of felt whilethe outside of the liner is typically made of a water resistantmaterial. In operation, the felt interior of the tubular liner is firstfilled with resin. The resin-filled liner is flattened and installedwithin the drum by coiling it around a spindle supported within thedrum. Once the liner is installed in the drum, the interior of the drummay be pressurized.

The pressure inside the drum operates to invert and expand the linerinto the existing pipe as it is discharged from the drum. Because theliner is inverted as it expands the length of the existing pipe, theresin soaked surface of the liner contacts the interior walls of thepipe. Water may be pumped into the interior of the inverted liner tohelp expand the liner throughout the pipe as the resin cures adjacent tothe pipe walls. In alternative embodiments, steam or UV light may beused to cure the resin to the pipe walls.

The resin used to saturate the liner is typically mixed with a hardeningagent. If the hardening agent sets before the liner is installed withinthe pipe, the liner is no longer usable. Thus, time is of the essencewith performing CIPP operations.

Inversion drums known in the art have access ports that are sealed usingmultiple threaded fasteners. Each fastener may have a knob that requiresa dozen or so revolutions before it becomes unfastened. Such fastenerstake time to engage or release. The covers used with such access portsalso typically need to be completely detached from the drum prior toinstalling the liner within the drum.

The present invention is directed to a latch assembly that allows rapidaccess to the interior of an inversion drum to quickly install a tubularliner within the drum. The latch assembly also allows for rapid sealingof the drum in order to quickly pressurize the interior of the drum.

With reference to FIG. 1, a pressurized inversion drum 10 is shown. Theinversion drum 10 comprises a cylindrical body 12 joined to a dischargecone 14. The body 12 is supported on a frame 16 and may be transportedusing a set of wheels 18 attached to the frame.

A tubular liner (not shown) is installed in the drum 10 through anaccess port 20. Once inside the drum 10, the liner is wound around aspindle 22 by a handwheel 24. The liner is discharged from the drum 10in an inverted form through the discharge cone 14. An air regulator 26,ball valve 28, and pressure gage 30 are supported on the top of the body12. These items allow an operator to pressurize the drum 10 for theinversion process. The operator may view the inside of the drum 10 usinga first sight glass 32 installed in the drum body 12.

The access port 20 is supported on the top of the drum 10 and comprisesa body 34 sealed by a cover 36. The cover 36 may be opened and closedusing a handle 38 attached to the cover. A second sight glass 40 isinstalled in the cover 36 in order to allow the operator to view theinside of the drum 10. A set of hose connections 42, 44 are alsoinstalled in the cover 36. The hose connections 42, 44 allow water to becirculated throughout the drum 10 to either retard or accelerate setupof the resin contained within the liner.

Turning to FIG. 2, the body 34 of the access port 20 comprises astandoff 46 having a central opening 48 formed therein. As shown in FIG.1, the bottom edge of the standoff 46 is attached to the body 12 of thedrum 10 and surrounds an opening (not shown) formed in the drum body 12.The tubular liner is installed within the drum 10 by passing through theopening 48 formed in the standoff 46 and the opening formed in the body12 of the drum 10.

A flange 50 is supported on the top edge of the standoff 46 thatsurrounds the central opening 48. The flange 50 is bounded by a firstend 52, an opposite second end 54, and side edges 56. Likewise, thecover 36 is bounded by a first end 58, an opposite second end 60, andside edges 62. Both the cover 36 and flange 50 have knuckles 64, 66formed on their second ends 54, 60 that are configured to mate andreceive a pin 68. Installation of the pin 68 within the knuckles 64, 66rotatably secures the cover 36 to the flange 50 in the form of a hingedjoint 70.

In alternative embodiments, the standoff 46 may not be used. Instead theflange 50 may be formed as part of the body 12 of the drum 10. In suchembodiment, the flange 50 would surround the opening (not shown) formedin the drum body 12.

FIG. 2 shows the cover 36 in an open position. The cover 36 is shown ina closed position in FIG. 1. The cover 36 rotates between an open andclosed position via the hinged joint 70. When closed, the cover 36 issized to cover the opening 48 and mate with the flange 50 such that theside edges 62 of the cover 36 are flush with the side edges 56 of theflange 50.

The cover 36 is locked to the body 34 by a latch assembly 72, theentirety of which is shown in FIGS. 10 and 13. With reference to FIGS.2-4, a portion of the latch assembly 72 comprises a plurality of spacedand aligned first knuckles 74 formed in the first end 58 of the cover36. Each of the first knuckles 74 extends downwards from the bottomsurface of the first end 58 of the cover 36. A first exposedsemi-cylindrical groove 76 is formed in the inner surface of each of thefirst knuckles 74. Each of the grooves 76 opens towards the second end60 of the cover 36. In one embodiment, the outer surface of each firstknuckle 74 is rounded.

The latch assembly 72, further comprises a plurality of spaced andaligned second knuckles 78 formed in the first end 52 of the flange 50adjacent the opening 48. Each of the second knuckles 78 is integral withthe first end 52 of the flange 50. A short cylindrical passage 80extends through each second knuckle 78. In one embodiment, the outersurface of each second knuckle 78 is rounded.

A notch 82 is formed in the first end 52 of the flange 50 between eachsecond knuckle 78. Each of the notches 82 are bounded on each side byadjacent second knuckles 78. A second exposed semi-cylindrical groove 84is formed in the flange 50 within each notch 82. Each of the grooves 84extends the length of each notch 82 and joins each passage 80 formed ineach second knuckle 78, as shown in FIG. 4.

The plurality of first knuckles 74 are spaced so that they arevertically alignable with each of the notches 82 in a one-to-onerelationship. Thus, when the cover 36 is rotated to a closed position,each of the first knuckles 74 is positioned within a corresponding oneof the notches 82. The plurality of first and second knuckles 74, 78 areinterlaced with one another when the cover 36 is in the closed position.In one embodiment, the outer surfaces of each first and second knuckle74, 78 are identical in shape and construction so as to form a smoothedge when interlaced.

When the knuckles 74, 78 are interlaced, each of the firstsemi-cylindrical grooves 76 aligns with a corresponding one of thesecond semi-cylindrical grooves 84 in a one-to-one relationship. Thealigned grooves 76, 84 join each of the short passages 80 so as to forma single passage, as shown in FIG. 13. As shown in FIGS. 2-3, each ofthe knuckles 74, 78 may vary in length. In alternative embodiments, eachof the knuckles 74, 78 may be the same length.

In alternative embodiments, the plurality of first knuckles 74 may beformed in the body 34 instead of the cover 36. In such case, theplurality of second knuckles 78 are formed in the cover 36 instead ofthe body 34.

Turning to FIGS. 5-6, the latch assembly 72 further comprises arotatable latch pin 86. The latch pin 86 has aligned and alternatingfirst and second sections 88, 90 that are bounded by a first and secondend 92, 94. Each first section 88 has a semicircular cross-sectionalshape resembling a half moon. Each first section 88 is complementary insize and shape to each of the first and second grooves 76, 84. The firstsections 88 are aligned with the longitudinal axis of the latch pin 86.

Each of the second sections 90 of the latch pin 86 has a size and shapecomplementary to the short cylindrical passages 80 formed in each of thesecond knuckles 78. The latch pin 86 is installed within the flange 50so that it extends through each second knuckle 78, as shown in FIG. 6.The length of each second section 90 may correspond with the length ofeach second knuckle 78.

A handle 96 is rigidly attached to each opposed end 92, 94 of the latchpin 86, as shown in FIG. 6. In one embodiment, each of the handles 96 isa rod that extends the length of each side edge 56 of the flange 50. Inalternative embodiments, only a single handle 96 may be attached to thelatch pin 86.

Turning to FIGS. 7-8, when the latch pin 86 is installed within theflange 50, each first section 88 is positioned within each second groove84 and each second section 90 is positioned within each short passage80. When the latch pin 86 is in this position, each of the notches 82 isclear to receive a corresponding one of the first knuckles 74, as shownin FIG. 7.

The latch assembly 72 is in the unlocked position when the notches 82are clear of the latch pin 86. In this position, the handles 96 arepositioned adjacent the side edges 56 of the flange 50, as shown in FIG.7. When the notches 82 are clear of the latch pin 86, the cover 36 mayrotate between its open and closed positions, as shown in FIGS. 1-2.

Clockwise rotation of the handles 98 rotates the latch pin 86 clockwisewithin the flange 50, and causes the latch assembly 72 to move from anunlocked to a locked position. Once the cover 36 is in a closedposition, the first and second knuckles 74, 78 are interlaced. With thecover 36 so positioned, the latch assembly 72 may be moved from theunlocked position to a locked position.

During an intermediate stage of the transition between unlocked andlocked positions, the latch assembly 72 reaches the engaged positionshown in FIGS. 9-11. Each of the first sections 88 has moved partiallyout of the second groove 84 and partially into the first groove 76, asshown in FIGS. 10-11. In this position, the latch pin 86 engages boththe first and second knuckles 74, 78.

Further clockwise rotation of the handles 96 moves the latch assembly 72from the engaged position to the locked position shown in FIGS. 12-14.Such rotation moves the first sections 88 entirely or substantiallyentirely within the first grooves 76, as shown in FIGS. 13-14. In thelocked position of the cover 36, the first knuckles are prevented frommoving vertically within the notches 82. Thus, the cover 36 is locked tothe flange 50.

The latch assembly 72 may be moved to an unlocked position bycounterclockwise rotation of the handles 96, which causes each firstsection 88 to move out of a first groove 76 and into a second groove 84.When the cover 36 is unlocked, the handles 96 are positioned adjacentthe sides edges 56 of the flange 50.

Once the first sections 88 are fully positioned in the first grooves 76,the first knuckles 74 are free to move out of the notches 82. Thus, thecover 36 is free to rotate about the hinge joint 70 to the openposition, shown in FIGS. 2 and 6.

Rotation of the handles 96 through an included angle of 180 degreesmoves the latch assembly 72 between its locked and unlocked positions.When the cover 36 is locked, as shown in FIG. 12, the handles extendaway from both the cover 36 and the flange 50. When the cover 36 isunlocked, the handles are positioned adjacent the side edges 56 of theflange 50.

When the interior of the drum 10 is under pressure, the locked latchassembly 72 can resist substantial opening forces applied to the cover36. The resistance is attributable to the lack of eccentricity betweenthe first sections 88 and the rotational axis of the latch pin 86. As aresult, there is no tendency for the force applied to the interior ofthe cover 36 to rotate the latch pin 86 to the unlocked position.

For example, if pressure within the drum is 40 psi, the latch assembly72 may resist up to 5,000 pounds of force applied to the cover 36. Yetthe latch assembly 72 needs only a relatively small amount of force toseal the cover 36 over the opening 48.

With reference to FIGS. 6, 10-11, and 13-14, a seal 98 is positioned onthe bottom surface of the cover 36. The seal 98 is sized to surround theopening 48, as shown in FIG. 6. The seal 98 engages the flange 50 whenthe cover 36 is in the closed position. In one embodiment, the seal 98is an O-ring. Locking of the latch assembly 72 compresses the seal 98tightly against the flange 50, so that pressure can be maintained in thedrum 10.

In alternative embodiments, the diameter of each first section 88 may beoffset from the longitudinal axis of the latch pin 86. Such designprovides a tighter lock between the first and second knuckles 74, 78 andin turn provides greater compression of the seal 96. Greater compressionmay be required if a larger seal is used in place of the O-ring shownherein.

With reference to FIGS. 15-19, an alternative embodiment of the latchassembly 100 is shown for use with the inversion drum 10. The latchassembly 100 uses the same cover 36, body 34, and latch pin 86 used withlatch assembly 72, shown in FIGS. 1-14. However, the latch assembly 100utilizes a different handle system 102.

Like handles 96, the handles 102 are rigidly attached to opposite ends92, 94 of the latch pin 86. Each of the handles 102 is substantiallyrectangular in shape and has a series of grips 104 formed on its bottomsurface. Unlike the handles 96, the handles 102 extend less than halfthe length of the side edges 56 of the flange 50.

With reference to FIGS. 17-19, the latch assembly 100 operates the latchpin 86 is the same manner as latch assembly 72. However, the handles 102are rotated clockwise to unlock the latch assembly 100, rather than tolock it. The first sections 88 are positioned within the second grooves84 when the handles 102 are extended away from the cover 36 and flange50.

With reference to FIGS. 15-16, the latch assembly 100 is in the lockedposition when the handles 102 are adjacent the flange 50. Positioningthe handles 102 adjacent the flange 50 when the latch assembly 100 is inthe locked position allows each of the handles 102 to be secured to theflange 50 by an independent lock mechanism 105. Securing the handles 102to the flange 50 provides a back-up lock in case the latch assembly 100fails.

In one embodiment, the lock mechanism 105 is a plunger 106 that may bedisposed within a bore 108 formed in each of the handles 102, as shownin FIG. 18. The plunger 106 is then secured to an opening (not shown)formed in the side edge 52 of the flange 50. In alternative embodiments,the lock mechanism 105 may comprise a threaded fastener or clamp. Inalternative embodiments, only one handle 102 may be used instead of two.

Changes may be made in the construction, operation and arrangement ofthe various parts, elements, steps and procedures described hereinwithout departing from the spirit and scope of the invention asdescribed in the following claims.

1. An apparatus, comprising: a body having an opening formed therein; a cover sized to cover the opening; and a latch assembly, comprising: a plurality of spaced and aligned first knuckles formed in a selected one of the cover and body, each first knuckle having an exposed semi-cylindrical groove formed therein; a plurality of spaced and aligned second knuckles formed in the unselected one of the cover and body adjacent the opening; and a rotatable latch pin having aligned and alternating first and second sections, each first section having a size and shape complementary to the semi-cylindrical groove of a first knuckle.
 2. The apparatus of claim 1 in which each second knuckle has a cylindrical passage extending therethrough.
 3. The apparatus of claim 2 in which each second section of the latch pin has a size and shape complementary to the cylindrical passage of a second knuckle.
 4. The apparatus of claim 1 in which the plurality of first and second knuckles are interlaceable.
 5. An apparatus, comprising: a pressurized inversion drum; and the apparatus of claim 1, in which the body and opening are those of the pressurized inversion drum.
 6. An apparatus, comprising: a drum having an opening; and the apparatus of claim 1 positioned over the opening.
 7. The apparatus of claim 1 in which a series of semi-cylindrical grooves are formed in the body between each second knuckle.
 8. A system, comprising: the apparatus of claim 6; and a tubular liner contained within the drum.
 9. The apparatus of claim 1 in which the latch pin is attached to a handle.
 10. The apparatus of claim 9 further comprising a lock mechanism attached to the handle.
 11. The apparatus of claim 1 further comprising a seal positioned on a bottom surface of the cover that is sized to surround the opening.
 12. The apparatus of claim 4 in which the latch assembly is in a locked position when the first and second knuckles are interlaced and each of the first sections of the latch pin are positioned within the grooves formed in each of the first knuckles.
 13. The apparatus of claim 7 in which the latch assembly is in an unlocked position when each of the first sections of the latch pin are positioned within the grooves formed in the body between each second knuckle.
 14. The apparatus of claim 1 in which the cover is rotatably attached to the body via a hinge joint.
 15. The apparatus of claim 1 in which the diameter of each first section is aligned with the longitudinal axis of the latch pin.
 16. The apparatus of claim 1 in which each of the first knuckles extend from the bottom surface of the cover.
 17. The apparatus of claim 1 in which each of the second knuckles is integral with the body.
 18. An apparatus, comprising: a body having an opening formed therein; a cover sized to cover the opening; and a latch assembly, comprising: a plurality of first knuckles formed in a selected one of the cover and body; a plurality of second knuckles formed in the unselected one of the cover and body adjacent the opening; in which the plurality of first knuckles are configured to interlace with the plurality of second knuckles; and a rotatable latch pin having a plurality of half-moon cross-sections.
 19. The apparatus of claim 18 in which a semi-cylindrical groove is formed in each of the first knuckles.
 20. The apparatus of claim 18 in which a semi-cylindrical groove is formed in the body between each second knuckle. 